The proposed investigation is designed to gain insight into the molecular events and regulatory mechanisms involved in the biogenesis of messenger RNA in mammalian cells. We will isolate large amounts of RNA polymerase type II from human placenta and characterize this enzyme at various stages of purification with regard to its subunit composition, catalytic properties, template preference, and specificity of interaction with a defined template in vitro. If S-100 extract is needed for specificity, it will be analyzed in much the same way as polymerase. Since large amounts of material will be required, we will continue our work on the aminimide-DNA polymer in order to adapt this affinity matrix for use in our high pressure liquid chromatography (HPLC) instrument. Although it may be beyond the scope of this proposal, results from experiments mentioned above, as well as those using the Waters Associates HPLC protein columns, may suggest an approach to preliminary reconstitution experiments. In addition to providing information concerning the properties of a human enzyme, these experiments should also bear on fundamental questions concerning the array of cell components required for the regulation of specific gene transcription in mammalian systems.